Formability study on stamping an engine hood with aluminum alloy sheet

Abstract

The formability of stamping an engine hood with aluminum alloy sheet was examined in the present study. In the stamping process, except that aluminum alloy would crack easily, a small elastic modulus makes the aluminum alloy easier to produce a significant springback defect, which would lead to variation of accuracy and is hard to grapple with. In the present study, the cyclic tension-compression reversal tests were first conducted to obtain the stress-strain relations and the Bauschinger effect exhibited in the aluminum alloy sheet was noted. The finite element simulations were then preformed for V-bending and U-hat drawing of aluminum alloy sheet, and the results of springback and side-wall curl were compared with those obtained from experiments. It is concluded from the comparison that the material model which includes the Bauschinger effect renders a more consistent result with the experimental data. In order to investigate the difference of forming characteristics between conventional steel and A6181-T4 in the stamping process of an engine hood, the effects of process parameters on the stamping formability were systematically analyzed by the finite element simulations. The finite element simulation results were validated by the production engine hood and the characteristics of A6181-T4 formability investigated in this study were confirmed.